In 2019, Sheridan sold 1000 units at $550 each, and earned net income of $76000. Variable expenses were $330 per unit, and fixed expenses were $144000. The same selling price is expected for 2020. Sheridan's variable cost per unit will rise by 10% in 2020 due to increasing material costs, so they are tentatively planning to cut fixed costs by $10000. How many units must Sheridan sell in 2020 to maintain the same income level as 2019?